Israeli missile attacks that killed 20 Palestinians in three days -- more than half of them civilians -- have reopened debate over the morality, effectiveness and political wisdom of Israel's strategy.

Israel considers the strikes a prime tool in its effort to destroy Palestinian militant groups, but critics say the assassinations have done little to stop terror.

"This is immoral, totally ineffective and it doesn't fit a democracy," said Yossi Beilin (search), the former justice minister who opposed the policy when it was adopted in November 2000. "These assassinations are capital punishment without trial."

From November 2000 until May 31, Israel killed at least 103 targeted people and 53 bystanders, according to the Israeli human rights group B'tselem (search). Since Tuesday, 20 more people died in four strikes -- at least a dozen of them bystanders.

Former Cabinet minister Ephraim Sneh (search) says the strikes are the most effective way to combat terror and wreck the infrastructure of militant groups.

"They are targeted. They are surgical, in most of the cases ... they are pinpointed toward the real masterminds, the organizers of the terror activity," he said. "These are the ones who ... brainwash the suicide bombers, these are the ringleaders, these are the people who gather the intelligence."

There is uncertainty about the attacks' effectiveness, and little evidence they have cowed militants. Generally the militant group Hamas (search) carries out revenge attacks -- as it did this week, when a suicide bomber killed 17 people in a Jerusalem bus blast.

However, many Israelis have concluded suicide attacks would continue in any case, and the militants must be fought.

Israel has long said it was targeting "ticking bombs" -- militants bound for terror attacks. But some targets have been top militant leaders, and in a few cases, the Palestinians claim they were politicians.

Israelis counter the title politician should not protect those inciting murder.

The new round of attacks began Tuesday with a failed effort to kill Abdel Aziz Rantisi, a Hamas leader Israel accuses of recent involvement in attacks.

It came less than a week after Israeli and Palestinian leaders launched the "road map" peace plan with President Bush, and two days after Palestinian militants killed five Israeli soldiers.

The strike against Rantisi was roundly criticized -- by Bush and by Israeli and Palestinian leaders -- as contributing to the cycle of Israeli-Palestinian violence.

On Wednesday, a Palestinian suicide bomber blew up a Jerusalem bus, an attack Hamas said was revenge for the strike against Rantisi.

Less than an hour later, an Israeli helicopter fired on a car carrying two Hamas militants in Gaza. The car exploded and Palestinians moved in to try to help. The helicopter returned and launched more missiles, killing seven other people, witnesses said.

"Is that the peace that they are talking about? Killing children, mothers and old men and leaving an open wound inside our hearts that will never be closed?" asked Nawal Daloul, who lost two cousins in the attack.

"Yesterday closed the small window of hope that I used to look forward to a good future," said Daloul, who was wounded along with her 3-year-old daughter Manel.

On Thursday, the helicopters struck again, hitting a car and killing two Hamas militants and five other people, including the wife and 2-year-old daughter of one of the militants.

Israeli military spokeswoman Maj. Sharon Feingold expressed regret at the civilian casualties from the Thursday attack. She said the wife and child "were not targets."

Feingold said Israel has called off many attacks for fear of civilian deaths.

B'tselem says the strikes are extrajudicial assassinations and the overwhelming force Israel often uses is out of proportion to the tactic's benefits.

"Israel and the government and the army do have the obligation to protect Israeli civilians, but they have to do it under the law," said Yael Stein, B'tselem's research director.

Israel's policy came under sharpest attack last July when an F-16 plane fired a laser-guided bomb into a building in Gaza City, killing Hamas leader Salah Shehadeh and 14 other people, including eight children.

Attacks like this degrade Israel's moral authority, Beilin said.

"When you take the liberty of assassinating these people, there is a big question about the limits. Where does it begin, where does it stop and who is the judge? Who decides who should be killed?" he asked.